The reference design is a high effiency (>94%) isolated AC/DC single string output LED lighting solution for high watt (>100W) general LED lighting. The topology uses Transition Mode (TM) PFC plus LLC control, which can support PWM dimming and analog dimming on the output side. The target application for this reference design is TV LED backlight, outdoor and high-bay general LED lighting. CT is eliminated in the design and the PSR controller UCC28700 is used for aux power in order to reduce overall cost.